Nozzle for use in the fabrication of a glazing unit

Abstract: A nozzle (104) for depositing the shaped layer of the piable material includes a platform (110) having a shaping tip (114). The shaping tip has converging sides at one end (116) and generally parallel sides at the other end (118). The portion of the tip at the first end (116) has a lower elevation than the portion of the tip at the second end (118). Holes (124,126) for moving the pliable material are provided in the platform (110) on each side of the tip (114) and in tips intermediate its ends. The different elevation and converging end (116) minimizes if not eliminates tailing.

Description: FIELD OF THE INVENTION This invention relates to a nozzle for use in the fabrication of a glazing unit, especially a nozzle for extruding a flowable material on a receiving surface. BACKGROUND OF THE INVENTION U.S. Patent No. 4,149,348 teaches a technique for making a triple glazed unit. In general, the triple glazed unit includes a pair of outer glass sheets separated by a spacer-dehydrator element, or metal spacer, having a groove to maintain a third glass sheet between the outer two glass sheets. DE-A-3 217 410, Fig. 6 discloses a nozzle with three openings for extruding a flowable material, comprising a platform 1 and a shaping member 2 mounted on the platform. As can be appreciated, it would be advantageous to provide a nozzle for extruding a flowable material for use in an insulating unit having three or more sheets that does not require storage of prefabricated materials e.g. a spacer-dehydrator element having a groove, does not require shaping the spacer to have a groove, and does not depend solely on the groove formed in the spacer to secure the intermediate sheet in position. SUMMARY OF THE INVENTION The invention relates to a nozzle as defined by claim 1 to deposit a shaped layer of the flowable material on a substrate. The nozzle includes a platform having a shaping tip or member mounted therein. The shaping tip at a first end has converging sides and at the opposite end has sides that are generally parallel to one another. Preferably, the elevation of the shaping tip at the first end is different e.g. lower, than the elevation of the shaping tip at the second end. Holes for moving material therethrough are in the nozzle, e.g. one hole on each side of the tip and one in the tip. The converging end of the tip and the different elevations of the tip minimize, if not eliminate, tailing when moving e.g. pumping of the material has been discontinued. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an elevated side view of a nozzle incorporating the features of the invention for extruding a shaped layer of adhesive on the base of a spacer. Fig. 2 is a plane view of the tip of the nozzle illustrating the features of the invention. Fig. 3 is a side view of the tip of the invention. Fig. 4 is a view similar to the view of Fig. 2 illustrating another embodiment of the invention. Fig. 5 is a view similar to the view of Fig. 3 illustrating further details of the tip of Fig. 4. Fig. 6 is a cross-sectional view of a triple glazed unit the nozzle according to the preceding figures may be used with for fabrication. BRIEF DESCRIPTION OF THE INVENTION In the practice of the invention a flat substrate was cut, notched, shaped, and the adhesive applied using the nozzle of the instant invention on, equipment sold by Glass Equipment Development Inc. of Twinsburg, Ohio, Model No. HME 55 PHE-L. Although not limiting to the invention, after the extrusion of a shaped layer 38, layers 32 are extruded onto the outer walls of outer legs 34 and 36 of a spacer 30. The sealant adhesive of the layer 32 used was sold by H. B. Fuller as H. B. Fuller 1191 hot melt butyl. The layer 32 had a thickness of about 0.020 inches (0.05 cm) and a height of about 0.300 inch (0.76 cm). As can be appreciated, the shaped layer 38 may be extruded onto the base of the spacer before, after, or during the extrusion of the layers 32 onto the side of the spacer. With reference to Fig. 6 there is shown a glazing unit 20. With specific reference to Fig. 6 the unit 20 includes a pair of outer sheets 22 and 24 and an intermediate sheet 26. The outer sheets 22 and 24 and the intermediate sheet 26 are maintained in spaced relationship by an edge assembly or spacer arrangement 28. In the following discussion the sheets 22, 24 and 26 are referred to as glass sheets; however, as will become apparent, the materials of the sheets are not limited to glass and any one or all of the sheets may be made of any similar or dissimilar material e.g. plastic, metal or wood. Further, one or more of the sheets may be coated e.g. glass or plastic transparent sheets may have an opaque coating of the type used in making spandrels. Still further, one or more of the glass or plastic transparent sheets may have an environmental coating on one or more of the sheet surfaces to selectively pass predetermined wavelength ranges of light. The outer glass sheets 22 and 24 may have the same peripheral configuration and dimensions; however, as can be appreciated, one outer glass sheet may be larger than the other outer glass sheet and may have a different peripheral configuration. The edge assembly 28 includes a spacer 30 having a generally U-shaped cross section as shown in Fig. 6, an adhesive layer 32 on outer surfaces of outer legs 34 and 36 of the spacer 30 and a shaped layer 38 of material on inner surface 40 of base 42 of the spacer 30. A layer 44 of a material similar to or dissimilar to the material of the layers 32 may be provided over outer surface 46 of the base 42 of the spacer 30 as shown in Fig. 6. As can be appreciated, the configuration of the spacer is not limiting to the invention and may have any cross section provided it has a surface to receive the shaped layer 38 and the intermediate glass sheet 26. As discussed, the spacer 30 may be made of any material and configuration that preferably provides structural stability to maintain the outer glass sheets 22 and 24 in spaced relationship to one another when biasing forces are applied to secure the glazing unit in a sash or a curtainwall system. Further the spacer 30 should have a substantially flat surface to receive the shaped layer 38. Although the spacer 30 may be made of any material and have any configuration provided it has a receiving surface, it is preferred that the spacer have low thermal conductivity so that the edge assembly 28 shown in Fig. 6 has a low thermal conductivity or high RES-value and is made of moisture and/or gas impervious materials. The heat loss through an edge of a unit is a function of the thermal conductivity of the materials used, their physical arrangement, the thermal conductivity of the frame and surface film coefficient. Surface film coefficient is transfer of heat from air to glass at the warm side of the unit and heat transfer from glass to air on the cold side of the unit. The surface film coefficient depends on the weather and the environment. Since the weather and environment are controlled by nature and not by unit design, no further discussion is deemed necessary. The frame or sash effect is not relevant in the present discussion because the discussion is directed to the thermal conductivity of the materials at the unit edge and their physical arrangement. The resistance of the edge of a unit to heat loss for an insulating unit having sheet material separated by an edge assembly is given by equation (1). (1) RHL = G1 + G2 + ... + Gn + S1 + S2 + ... + Sn where RHL is the resistance to edge heat loss at the edge of the unit in hour - DEG F/BTU/inch of unit perimeter (Hr- DEG F/BTU-in.) G is the resistance to heat loss of a sheet in Hr- DEG F/BTU-in. S is the resistance to heat loss of the edge assembly in Hr- DEG F/BTU-in. For an insulating unit having two sheets separated by a single edge assembly equation (1) may be rewritten as equation (2). (2) RHL = G1 + G2 + S1 The thermal resistance of a material is given by equation (3). (3) R = L/kA where R is the thermal resistance in Hr- DEG F/BTU-in. k is thermal conductivity of the material in BTU/hour-inch- DEG F. l is the thickness of the material as measured in inches along an axis parallel to the heat flow. A is the area of the material as measured in square inches along an axis transverse to the heat flow. The thermal resistance for components of an edge assembly that lie in a line substantially perpendicular or normal to the major surface of the unit is determined by equation (4). (4) S = R1 + R2 + ... + Rn where S and R are as previously defined. In those instances where the components of an edge assembly lie along an axis parallel to the major surface of the unit, the thermal resistance (S) is defined by the following equation (5). (5) R = 1 1 R 1 + 1 R 2 + ... + 1 R n where R is as previously defined. Combining equations (2), (4) and (5), the resistance of the edge of the unit 20 shown in Fig. 6 to heat flow may be determined by following equation (6). (6) RHL = R 22 + R 24 + 2R 32 + 2R 34 + 1 1 R 42 + 1 R 38 + 1 R 44 where RHL is as previously defined, R22 and R24 are the thermal resistance of the glass sheets, R32 is the thermal resistance of the adhesive layer 32, R44 is the thermal resistance of the adhesive layer 44, R34 is the thermal resistance of the outer legs 34 of the spacer 30, R42 is the thermal resistance of the base 42 of the spacer 30, R38 is the thermal resistance of the adhesive layer 38, and R26 is the thermal resistance of the middle sheet 26. For ease of discussion, equation (6) does not consider the thermal conducting contribution of the intermediate sheet 26. If the thermal conductivity contribution of the intermediate sheet 26 were considered, it is expected that the value of RHL in equation (6) would be about 10% higher than the value calculated without considering the contribution of the thermal conductivity of the intermediate sheet 26. Although equation (6) shows the relation of the components to determine edge resistance to heat loss, Equation (6) is an approximate method used in standard engineering calculations. Computer programs are available which solve the exact relations governing heat flow or resistance to heat flow through the edge of the unit. One computer program that is available is the thermal analysis package of the ANSYS program available from Swanson Analysis Systems Inc. of Houston, PA. With continued discussion of the instant invention, the materials of the adhesive layers 32 and the layer 44 are not limiting to the invention and are preferably a material that is moisture and/or gas impervious to prevent the ingress of moisture into the compartment between the sheets. Although not limiting to the invention, butyl hot melts of the type sold by H. B. Fuller e.g. H. B. Fuller 1191 may be made in the practice of the invention. Units filled with an insulating gas e.g. Argon preferably have the adhesive layer 32 and the layer 44 of a moisture and/or gas impervious material to maintain the insulating gas in the compartment between the sheets 24, 26 and 26, 22. It is recommended that the adhesive layer 32 or sealant layer 32 be thin and long to reduce the diffusion of the insulating gas out of the compartments of the unit or atmosphere's gas into the compartments of the unit. More particularly, increasing the thickness of the layer 32 i.e. the distance between the glass sheet and the adjacent leg of the spacer while keeping all other conditions constant increases the diffusion rate, and increasing the length of the layer 32 i.e. the distance between the top of the outer leg of the spacer and the peripheral edge of the sheets or the outer surface 46 of the spacer 30 as viewed in Fig. 6 while keeping all other conditions constant decreases the diffusion rate of gas through the adhesive layer 32. The invention may be practiced with the adhesive layer 32 having a thickness less than about 0.125 inch (0.32 cm) and more particularly, of about 0.005 inch (0.013 cm) to about 0.125 inch (0.32 cm), preferably about 0.010 inch (0.025 cm) to about 0.020 inch (0.050 cm) and most preferably about 0.015 inch (0.38 cm), and a height of greater than about 0.010 inch (0.025 cm), and more particularly, of about 0.010 inch (0.025 cm) to about 0.50 inch (1.27 cm), preferably about 0.125 inch (0.32 cm) to about 0.50 inch (1.27 cm) and most preferably about 0.200 inch (0.50 cm). As can be appreciated the thickness and length of the layer 32 may change as the moisture and/or gas resistance value of the moisture and/or gas impervious material changes. For example as the resistance value of the material increases, the thickness of the layer 32 may be increased and the length of the layer 32 decreased and as the resistance value of the material decreases, the thickness of the layer 32 should be decreased and the length of the layer 32 should be increased. Adhesives that may be used in the practice of the invention include but are not limited to butyls, silicons, polyurethane adhesives and are preferably butyls and polyurethanes such as H. B. Fuller 1191, H. B. Fuller 1081A and PPG Industries, Inc. 4442 butyl sealant. With respect to the loss of the fill gas e.g. an insulating gas such as Argon from the unit, in practice the length and thickness of the layer 32 are chosen in combination with the gas permeability of the material so that the rate of loss of the fill gas matches the desired unit performance lifetime. The ability of the unit to contain the fill gas is measured using a European procedure identified as DIN 52293. Preferably, the rate of loss of the fill gas should be less than 5% per year and, more preferably, it should be less than 1% per year. The preferred material for the layer 32 should have a moisture permeability of less than 20 gm mm/M 2 day using ASTM F 372-73 and more preferably less than 5 gm mm/M 2 day. As can be appreciated, the spacer 30 should also be made of a material that is moisture and/or gas impervious e.g. metal or plastic such as but not limited to metal coated steels, stainless steel, gas pervious spacers covered with a metal or polyvinylidene chloride film and/or a halogenated polymeric material. In Fig. 6 there is shown the layer 44 provided on the outer surface 46 of the spacer 30. The layer 44 may be a material similar to the material of the layers 32 and is preferably non-tacky so that the units when stored or shipped do not stick to the supporting surface. Further when the units have the layer 44, the spacer 30 is preferably below the peripheral edges of the sheets 22 and 24 to provide a channel to receive the layer 44. The thickness of the layer 44 is not limiting to the invention and where used increases the RES-value because of the thermal insulating properties of the sealant. The invention may be practiced with no layer 44 to a layer 44 having a thickness of about 0.50 inch (1.27 cm), preferably about 0.062 inch (0.16 cm) to about 0.250 inch (0.64 cm) and most preferably about 0.150 inch (0.38 cm). Preferably the layer 44 has similar moisture and gas resistance values on the layers 32. With specific reference to Fig. 6, the layer 38 is shaped to provide a groove 48 to receive the peripheral edge of the intermediate sheet 26. The material selected for the layer 38 is a material that is flowable onto the receiving surface 40 of the base 42 of the spacer 30 and adheres thereto as contrasted to a preformed material of the type taught in U.S. Patent No. 4,149,348. Using a flowable material in accordance to the disclosure of the instant invention provides for ease of automating the fabrication of the spacer, edge assembly and/or units, as will be appreciated in the following discussion. The term "flowable material" means a material that may be flowed onto a surface, for example but not limited to the invention by extrusion or pumping. In the selection of the materials for the layer 38, consideration has to be given to maintaining the intermediate sheet 26 in position, e.g. prevent or limit its movement toward one of the outer sheets. Materials that are most preferably used in the practice of the invention are those materials that are flowable and remain pliable after flowing and materials that are flowable and harden e.g. are dimensionally stable after flowing. The term "pliable materials" means materials that have a Shore A Hardness of less than 45 after 10 seconds under load. Pliable materials that may be used in the practice of the invention have a Shore A Hardness of less than 40 after 10 seconds. Pliable materials used in the practice of the invention had a Shore A Hardness of 25 with a range of 20-30 after 10 seconds. The term "hardened material" is a material other than a pliable material. In the instance where the intermediate sheet 26 is to be held in position only by the shaped layer 38, the layer 38 should be a material that is flowed onto the surface 40 of the spacer to provide the groove layer 38, and, thereafter, the material is sufficiently rigid to maintain the intermediate glass sheet in position. In the instance where the material is flowed onto the base and is not sufficiently rigid, it is recommended that facilities be provided to secure the intermediate glass in position. Also if the material of the layer 38 requires time to become sufficiently rigid and the unit is to be moved prior to setting of the layer 38, it is recommended that facilities be provided to secure the intermediate glass in position. The preferred manner in either instance is to use the spacer 30 alone or in combination with the layer 38 in a manner to be discussed below. Other external facilities such as spacer blocks may be used in the practice of the invention. With reference to Fig. 6, continuous corners are formed by portions 58 (see Fig. 6) of the legs 34 and 36 of the spacer 30 biased toward one another at the corner over the receiving surface 40 of the spacer 30. As the bent portions 58 of the legs 34 and 36 are urged toward one another, portions 60 of the shaped layer 38 are moved against the intermediate glass sheet and are shown by numeral 60 in Fig. 6. In the instance where the layer 38 is to carry the desiccant to keep the space between the sheets i.e. compartments dry, the material should be a moisture pervious material. Materials having a permeability greater than 2 gm mm/M 2 day as determined by the above reference to ASTM F 372-73 are recommended. With reference to Fig. 6, the ends of the upright legs 34 and 36 are radiused inwardly to provide stability to the spacer e.g. to reduce flexing of the spacer 30 prior to bending it around the glass sheet 26. After the substrate is shaped, the shaped layer 38 were provided by extruding H. B. Fuller HL-5102-X-125 butyl hot melt matrix having a desiccant therein is flowed onto the base of the spacer in using a nozzle arrangement to be discussed below incorporating the features of the invention. As can be appreciated, the invention is not limited to the equipment for providing the shaped layer 38. Each of the raised portions of the shaped layer 38 had a height of 0.125 inch (0.32 cm) and a width of 0.255 inch (0.64 cm) to provide a groove having a depth of 0.093 inch (0.23 cm) and a width of 0.125 inch (0.32 cm). It is preferred to have the material of the layer 38 under the sheet to eliminate any contact between the sheet and the base of the spacer to prevent damage to the edge of the sheet. The outer glass sheets 22 and 24 were positioned over the sealant adhesive 32 and biased toward one another to flow the adhesive 32 and secure the outer glass to the spacer. Thereafter the adhesive 44 was flowed into the channel formed by the peripheral edges of the sheets and the base of the spacer. The discussion will now be directed to a nozzle incorporating the features of the invention used to provide the shaped layer 38. With reference to Figs. 1-3 there is shown nozzle arrangement 100 having a conditioning chamber 102 and a nozzle 104 secured thereto in any convenient manner e.g. by screws. The conditioning chamber 102 is connected by hose or conduit 106 to a supply of the adhesive material (not shown). In the instance where the material is a hot melt adhesive, the conditioning chamber 102 is provided with heating elements to heat the adhesive to its flow temperature; in the instance where the adhesive is a two component adhesive, the adhesive is mixed in the conditioning chamber 102. With specific reference to Figs. 2 and 3, the nozzle 104 has a base 108 supporting a raised platform 110 having a pair of opposite flat sides 112 clearly shown in Fig. 2. The platform 110 has a forming surface including a forming tip 114 that forms the shaped layer 38 in a manner to be discussed. The forming tip 114 has a generally arrow shaped end 116 narrower than opposite end 118. The end 116 is lower in height than the end 118 with the end 118 sloping toward the platform 110 as shown by numeral 120 in Fig. 3. In practice the U-shaped spacer 30 advances from left to right as shown in Fig. 3. As the lead end of the spacer 30 engages the tip 114 the sloped end 120 biases the leading end of the spacer downward as viewed in Fig. 3 against conveyor 122 in those instances where the lead end of the spacer is raised. As the spacer advances past the nozzle 104 the adhesive is extruded through holes 124 and 126 onto the base of the spacer as the forming tip 114 shapes the adhesive to provide the shaped layer 38 on the base of the spacer. In the practice of the invention for making the unit discussed above, the base 108 had an outside diameter of about 2-1/2 inches (6.35 cm) and a thickness of about 1/4 inch (0.635 cm). The platform 110 had a height of about 3/8 inch (0.95 cm). The platform was circular with a diameter of about 0.52 inch (1.37 cm) except for the flat sides 112 that are spaced from each other about 0.485 inches (1.23 cm) and each have a length of about 0.23 inch (0.53 cm). The tip 114 at the narrow end 116 has a width of about 0.028 inch (0.020 cm) and expands toward the center line of the tip to a width of about 0.062 inch (0.157 cm). The slope surface 120 starts at the edge of the platform 110 and terminates about 0.125 inch (0.37 cm) therefrom. With reference to Fig. 3, the tip 114 at the sloped end 118 has a height of about 0.080 inch (0.20 cm) and at the narrow end 116 of about 0.065 inch (0.165 cm). The holes 124 in the platform each had a diameter of about 0.120 inch (0.3 cm) and the hole 126 in the tip had a diameter of about 0.093 inch (0.236 cm). In practice, H. B. Fuller adhesive HL-5102-X-125 having a desiccant therein is heated to about 250°F (121°C). As the U-shaped spacer 30 moves past the nozzle 104, the platform 110 is positioned between the outer legs 34 and 36 of the spacer with the highest portion of the tip 114 e.g. end 118 of the tip spaced about 1/32 inch (0.08 cm) from the base 42 of the spacer 30. As the spacer 30 moves past the nozzle the sloped end 120 urges the leading edge of the spacer downward, if lifted, toward the conveyor as adhesive is extruded from the holes 124 and 126 to provide the shaped layer 38. The narrow portion of the tip and the step of the tip prevent tailing of the adhesive when the flowing e.g. pumping or extrusion of the material is stopped. It is expected that providing a step for the platform 110 similar to that of the tip will further ensure elimination of tailing. With reference to Figs. 4 and 5, there is shown nozzle 130 having platform 132. The nozzle 130 is similar to the nozzle 104 except the platform 132 is provided with a lower portion 134 and a raised portion 136 and the platform and nozzle where the change in elevation occurs is radiused surface 140 as shown in Fig. 4. It is expected that the radiused surfaces 140 and change in elevation will eliminate tailing. The term "tailing" as used herein is the noted effect that occurs when the flowing e.g. pumping or extrusion of the material is stopped but due to the adhesive adhering to the nozzle, strings of adhesive are pulled. As can now be appreciated the invention is not limited to making a triple glazed unit. For example there may be a unit having four glass sheets. When more than three sheets are used, a blank or spacer may be used between glass sheets. Further, the intermediate sheet may have a hole drilled therein to interconnect the compartments of the triple glazed unit.

Claims: A nozzle (104,130) for extruding a flowable material comprising: a platform (110,132), a shaping member (114) mounted on the platform (132), the shaping member (114) having one end (116) that has converging sides defined as the first end and the other end (118) having generally parallel sides defined as the second end, and a hole (124) in the platform (110,132) on each side of the shaping member (114) for extruding flowable material and a hole (126) in the shaping member (114) for extruding flowable material. The nozzle (104,130) of claim 1 wherein the second end (118) has a sloping surface (120). The nozzle (104,130) of claim 1 or 2 wherein the elevation of the first end (116) and the second end (118) are different. The nozzle (104,130) of claim 3 wherein the surface of the first end (116) is closer to the platform (110,132) than the second end (118). The nozzle (104,130) of any of claims 1 to 4 wherein the opposed sides (112) of the platform (110,132) are flat and generally parallel to one another. The nozzle (104,130) of claim 5 wherein the platform (132) has different elevations defined by a wall (140) that is radiused. The nozzle (104,130) of claim 1 or 6 further includes: a conditioning chamber member (102), a base (108) secured to an end of the chamber member (102), and the platform (110,132) secured to the base (108). The nozzle (104,130) of claim 7 wherein the conditioning chamber member (102) includes heating means. The nozzle (104,130) of claim 1 wherein the platform (132) is provided with a lower portion (134) and a raised portion (136). The nozzle (104,130) of claim 9 wherein radiused surface (140) is provided where the change in elevation occurs. The nozzle of claim 5 wherein the surface of the platform (132) adjacent the second end (118) of the shaping member (114) and on each side thereof has an elevation, the elevation on each side of the shaping member being less than the elevation of the surface of the second end (118) of the shaping member (114) and greater than the elevation of the surface of the platform (110) adjacent the first end (116) of the shaping member with the elevation on each side of the shaping member having a radiused portion (140) facing the first end (116) of the shaping member (114). The nozzle of claim 2 wherein the sloping surface (120) at the second end (118) of the shaping member (114) starts at the edge of and extends from the platform (110).

Inventors: KOVACIK PAUL J, LEOPOLD EDMUND A, KOVACIK, PAUL J., LEOPOLD, EDMUND A.
Applicants: PPG IND OHIO INC, PPG INDUSTRIES OHIO, INC.
Application year: 1994
Main classification: E06B3
IPC codes: E06B3, B29C47